The UnknownFormatConversionException is an unchecked exception in Java that occurs when an unknown conversion is given. Since the UnknownFormatConversionException is thrown at runtime, it does not need to be declared in the throws clause of a method or constructor.

The MissingFormatArgumentException is an unchecked exception in Java that occurs when a format specifier does not have a corresponding argument or if an argument index points to an argument that does not exist. Since the MissingFormatArgumentException is thrown at runtime, it does not need to be declared in the throws clause of a method or constructor.

p>The InputMismatchException is a runtime exception in Java that is thrown by a Scanner object to indicate that a retrieved token does not match the pattern for the expected type, or that the token is out of range for the expected type. Since InputMismatchException is an unchecked exception, it does not need to be declared in the throws clause of a method or constructor.

The java.awt.HeadlessException is a runtime exception in Java that occurs when code that is dependent on a keyboard, display or mouse is called in an environment that does not support a keyboard, display or mouse. Since HeadlessException is an unchecked exception, it does not need to be declared in the throws clause of a method or constructor.

To run Java applications optimally, the JVM divides memory into stack and heap memory. Whenever new variables and objects are declared, new methods are called or other similar operations are performed, the JVM designates memory to these operations from either the Stack Memory or Heap Space. Heap space is used for the dynamic memory allocation of Java objects and classes at runtime. New objects are always created in the heap space, and references to these objects are stored in the stack memory.

Like most modern programming languages, Java includes the concept of exceptions to handle both errors and "exceptional events." When an exception occurs in your code, it disrupts the normal instruction logic and abnormally terminates the process. However, with a little foresight and code, you can often handle these exceptions gracefully, allowing your code to continue running and providing insight for tracking down the root cause of the unexpected result.

The NoClassDefFoundError is a runtime error in Java that occurs if the Java Virtual Machine (JVM) or a ClassLoader instance attempts to load the definition of a class that could not be found. The class definition exists at compile-time but is not available at runtime.

A Java stack trace is displayed when an error or exception occurs. The stack trace, also called a backtrace, consists of a collection of stack records, which store an application's movement during its execution. The stack trace includes information about program subroutines and can be used to debug or troubleshoot and is often used to create log files. These exceptions could be custom (defined by the user) or built-in.

Try-catch blocks in PHP can be nested up to any desired levels and are handled in reverse order of appearance i.e. innermost exceptions are handled first. Nested blocks can be useful in case a block of code causes an exception, which can be handled within that block and program execution can continue in the outer block. They can also be useful in case the handling of an exception causes another exception.

The Javascript ReferenceError occurs when referencing a variable that does not exist or has not yet been initialized in the current scope. Reference errors in Javascript are of a few different types, with variations of each, that may get triggered in code. Some of these are discussed below.